000
FXUS63 KTOP 100314
AFDTOP
AREA FORECAST DISCUSSION
National Weather Service Topeka KS
914 PM CST Fri Dec 9 2016
.UPDATE...
Issued at 912 PM CST Fri Dec 9 2016
Have increased sky cover through the overnight and fine-tuned the
timing of the back edge of the stratus shield as it works across
the CWA. Likewise adjusted temperatures under the clouds to
account for minimal radiational cooling until skies clear. This
has resulted in a 3 to 5 degree increase in MinT values in the
east where the stratus may depart until after sunrise.
&&
.SHORT TERM...(This evening through Saturday)
Issued at 243 PM CST Fri Dec 9 2016
Strong surface high pressure was shifting east of the area today
while low pressure was strengthening in the lee of the Rockies.
Upper level flow was northwesterly with a few weak waves moving
through the flow and a stronger upper wave and jet streak
approaching the Pacific northwest. Locally, there will be no areas
of focused forcing and limited moisture so precip is not in the
forecast through Saturday.
Widespread cloud cover has kept temperatures in check today with
highs only in the 20s as winds turned out of the south and
southeast. The stratus deck is not particularly thick but expect
weak isentropic ascent and the existence of saturation through the
layer to keep clouds in place for much of the night and perhaps into
Saturday. This will keep overnight low temperatures a bit warmer and
currently forecast to fall only into the middle teens. Saturday high
temperatures will depend largely on the extent of cloud cover and
current indications are that clouds will break by afternoon and
allow temperatures to warm into the upper 30s to around 40 degrees,
but with a south breeze occasionally gusting 20 to 25 mph.
.LONG TERM...(Saturday night through Friday)
Issued at 243 PM CST Fri Dec 9 2016
Upper shortwave trough tracking over the northwest conus is progged
to deepen as the axis enters the northern plains Sunday morning.
Last few model runs are showing better agreement in the timing of
the sfc front holding the freezing temperatures across far northern
Kansas, while temps along and south of Interstate 70 increase from
the middle 30s Sunday morning to the lower 40s in the afternoon as
warmer air advects into the region from the southwest. Saturation in
the lowest 800 mb contribute to the potential for light drizzle
during the day while better forcing and moisture availability occurs
just to our east in Missouri. Temperatures initially in the morning
hover near freezing across far northeast Kansas. Therefore I
mentioned a slight chance for freezing drizzle. System quickly
clears east by Sunday evening with high pressure building in Monday
with clear skies and mild temperatures near 40 degrees.
A stronger shot of colder air arrives Tuesday evening behind another
cold front in the evening, cooling highs back into the 20s through
Friday with lows in the teens and perhaps single digits. Its
interesting to note that the GFS solutions have trended much
stronger and colder with this arctic airmass resulting in
temperatures potentially being even colder than current forecast.
Strong upper low builds down through Canada as an incoming shortwave
trough deepens southeast over the western CONUS Tuesday and
Wednesday. Depending on the position of the upper low will determine
the track of this system, with the GFS bringing widespread winter
precipitation to Kansas, while the ECMWF is further north into
Nebraska. Temperature profiles suggest precip type to be all snow at
this time. Have 30 percent pops in there for now as solutions are to
change in the coming periods.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 537 PM CST Fri Dec 9 2016
Low VFR CIGS are expected this evening and tonight, gradually
clearing from west to east. Winds will remain from the SE through
the period around 5 kts tonight, increasing to between 10 and 15
kts tomorrow.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Skow
SHORT TERM...Barjenbruch
LONG TERM...Prieto
AVIATION...Skow